Availability-based design optimization of offshore wind farm

1. Availability-based design optimization of offshore wind farm PhD Candidate: Cyril Boussion Department: AWEP Section: Wind Energy Supervisor: G. van Bussel Promoter: G. van Bussel Start date: 01-02-2012 Funding: FLOW Background and aim Offshore wind is a promising energy resource in order to face the climate change and to reduce the gas emissions. Over the last decade, this sector has experienced a very rapid growth, wind turbines have become powerful and wind parks bigger. However, the availability of the wind farms is still low, the costs for a repair are increasing and the loss of energy is high if a turbine stops. This research aims to find ways to increase the availability of offshore wind farms. Availability is a critical issue for offshore wind farms The availability is a function of machine properties, site accessibility and maintenance strategy: • + Low accessibility • + Harsh environment • + High travel time • + … • Low availability • High O&M costs The availability of a wind turbine is the percentage of time it is mechanically able to produce electricity. Reliability failures/year Accessibility to the site • IEA Wind Task 33 on Reliability data • I am involved in a task group, with FraunhoferIWES, Sandia National Laboratories, Chalmers University, China Wind Energy Association, DTU, Vattenfall, etc. • The purpose is to improve the “Standardization of data collection for wind turbine reliability and maintenance analyses”. Real availability Theoreticalavailability Maintainability ease of repair Serviceability ease of service Maintenance strategy Examples of maintenance operations on offshore wind turbines (source: Areva, Siemens) Optimization of the sensor network use Current situation On a wind turbine (WT), hundreds of sensors are found at different location and used for control and performance optimization, but also condition-based maintenance. Unfortunately, a high number of sensors leads to more complexity in the analysis. A reasoning system can improve the data analysis First finding The current working state can be identified with only six sensors: wind speed, ambient temperature, pitch angle, yaw angle, power output, rotational speed. The reasoning system building is in progress! Design for reconfiguration If a minor failure occurs, the wind turbine may be able to work anyway. A function of the wind turbine may be carried out in a different way, until the failure is repaired. During that period, the efficiency and the performance of the wind turbine are usually lower than during the normal operation mode. Thispart of the thesis has not been started yet. Aerospace Engineering Example of reconfiguration Wind turbine working and healthy The pitch system is repaired by the maintenance crew Reconfiguration: Stall control instead of pitch control Pitch system fails, turbine stopped Wind turbine working but not healthy Progress and objectives Progress in the PhD: The GO decision was taken last December. The first conference presentation will be done next September at Stanford University, Stanford CA, USA. Next step in the research: Include new sensors in the reasoning system and test it with real data. Start the reconfiguration part. • Publications • C.G.F. Boussion, G.J.W van Bussel, “Optimization of the information needed for wind turbine health monitoring”, International Workshop on Structure Health Monitoring 2013, Stanford University, Stanford CA, USA, to be published